From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 49BDBC48BE5 for ; Wed, 16 Jun 2021 23:16:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D0056100A for ; Wed, 16 Jun 2021 23:16:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234365AbhFPXSR (ORCPT ); Wed, 16 Jun 2021 19:18:17 -0400 Received: from mga01.intel.com ([192.55.52.88]:36141 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234364AbhFPXSR (ORCPT ); Wed, 16 Jun 2021 19:18:17 -0400 IronPort-SDR: mCrqcvpDm0KodAI/3lrFE/+rt9N+ailDaHwtjPenv9e//bce8Ztb9NSwIyC+/GoOeTRQyHDet5 Q3sRPZW3WP0w== X-IronPort-AV: E=McAfee;i="6200,9189,10017"; a="227778821" X-IronPort-AV: E=Sophos;i="5.83,278,1616482800"; d="scan'208";a="227778821" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Jun 2021 16:16:10 -0700 IronPort-SDR: QEB0nCtcQDbfd2iL9XbdtZmiPBj3V+5e+bpkDfzovMfKb1y4dKe/IUcJ65uFG5hfDAqPPG68Y+ WibriOKCa5yg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.83,278,1616482800"; d="scan'208";a="472210731" Received: from alison-desk.jf.intel.com ([10.54.74.53]) by fmsmga004.fm.intel.com with ESMTP; 16 Jun 2021 16:16:10 -0700 Date: Wed, 16 Jun 2021 16:11:54 -0700 From: Alison Schofield To: Ben Widawsky Cc: Dan Williams , Ira Weiny , Vishal Verma , linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, Linux ACPI Subject: Re: [PATCH v2 1/2] cxl/acpi: Add the Host Bridge base address to CXL port objects Message-ID: <20210616231154.GA25185@alison-desk.jf.intel.com> References: <20210616160816.ollsqeyhpnjm5oq2@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210616160816.ollsqeyhpnjm5oq2@intel.com> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org Thanks for the review Ben - On Wed, Jun 16, 2021 at 09:08:16AM -0700, Ben Widawsky wrote: > On 21-06-15 17:20:38, Alison Schofield wrote: > > The base address for the Host Bridge port component registers is located > > in the CXL Host Bridge Structure (CHBS) of the ACPI CXL Early Discovery > > Table (CEDT). Retrieve the CHBS for each Host Bridge (ACPI0016 device) > > and include that base address in the port object. > > > > Co-developed-by: Vishal Verma > > Signed-off-by: Vishal Verma > > Signed-off-by: Alison Schofield > > --- > > drivers/cxl/acpi.c | 105 ++++++++++++++++++++++++++++++++++++++++++--- > > 1 file changed, 99 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c > > index be357eea552c..b6d9cd45428c 100644 > > --- a/drivers/cxl/acpi.c > > +++ b/drivers/cxl/acpi.c > > @@ -8,6 +8,61 @@ > > #include > > #include "cxl.h" > > > > +static struct acpi_table_header *cedt_table; > > cedt_header would really be a better name. "Table" is redundant as the 't' in > CEDT is table. > Agree. Renamed to acpi_cedt in v3. See if you like. > > + > > +static struct acpi_cedt_chbs *cxl_acpi_match_chbs(struct device *dev, u32 uid) > > +{ > > + struct acpi_cedt_chbs *chbs, *chbs_match = NULL; > > + acpi_size len, cur = 0; > > + void *cedt_base; > > maybe "cedt_body", or "cedt_subtables" got it in v3. > > > + int rc = 0; > > + > > + len = cedt_table->length - sizeof(*cedt_table); > > + cedt_base = cedt_table + 1; > > As per naming recommendation above, this looks really funny... > :) > > + > > + while (cur < len) { > > + struct acpi_cedt_header *c = cedt_base + cur; > > Okay, now I see why you may have not called the previous thing a header. > > > + > > + if (c->type != ACPI_CEDT_TYPE_CHBS) { > > + cur += c->length; > > + continue; > > + } > > + > > + chbs = cedt_base + cur; > > + > > + if (chbs->header.length < sizeof(*chbs)) { > > + dev_err(dev, "Invalid CHBS header length: %u\n", > > + chbs->header.length); > > + rc = -EINVAL; > > + break; > > + } > > I'd just continue here. Maybe there will be another chbs with the correct size. > Got it. > > + > > + if (chbs->uid == uid && !chbs_match) { > > + chbs_match = chbs; > > + cur += c->length; > > + continue; > > + } > > + > > + if (chbs->uid == uid && chbs_match) { > > + dev_err(dev, "Duplicate CHBS UIDs %u\n", uid); > > + rc = -EINVAL; > > + break; > > + } > > I'd also just continue here. I think if we have a match, we can just use it and > ignore BIOS bugs. I'd probably write it like this: > > if (chbs->uid == uid) { > dev_WARN_ONCE(dev, chbs_match, "Duplicate CHBS UIDs %u\n", uid); > chbs_match = chbs; /* last one wins */ > cur += c->length; > continue; > } > > Up to you how you actually write it, but do consider not failing here. > Thanks for the snippet. I added the dev_WARN_ONCE to both the length mismatch and duplicate cases. > > + cur += c->length; > > + } > > + if (!chbs_match) > > + rc = -EINVAL; > > Maybe ENODEV or something like it is more appropriate? Got it. > snip